Method for feeding back channel state information, ue and system

ABSTRACT

A method for feeding back channel state information, UE and system. The method is applicable to a CoMP transmission system and includes: feeding back channel state information to a network side by way of concatenating more than one pieces of channel state indication information in a bit domain. In this way, a method for feeding back multiple pieces of CSI in the CoMP transmission may be provided. Furthermore, RI information and CQI/PMI information in the CSI may be respectively encoded and mapped, so as to ensure reliable transmission of the RI information and CQI/PMI information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of International Application No.PCT/CN2012/077116, filed on Jun. 18, 2012, now pending, the contents ofwhich are herein wholly incorporated by reference.

TECHNICAL FIELD

The present invention relates to the field of communications, and inparticular to a method for feeding back channel state information, UEand system.

BACKGROUND ART

In a long-term evolution advanced (LTE-A) system, a coordinatedmulti-point (CoMP) transmission technology is introduced to enhanceperformance of a cell-edge user, and improve an average throughput ofthe cell at the same time.

In LTE-A Rel. 11, a downlink CoMP technology is standardized for jointtransmission (JT), dynamic point selection and coordinatedscheduling/beamforming. In order to accurately perform link adaptivetransmission and effectively obtain a gain of the CoMP transmission, UEneeds to accurately feed back for different transmission assumptions.

As the UE is limited in an actual processing ability, the number ofpieces of channel state information (CSI) reported by the UE is limited.In the CoMP transmission, as multiple pieces of CSI corresponding todifferent transmission points and interference assumptions need to bereported, there is no effective method for reporting CSI at present forthe CoMP transmission.

SUMMARY OF THE INVENTION

An object of embodiment of the present invention is to provide a methodfor feeding back channel state information, UE and system; whereinfeedback of multiple pieces of CSI in CoMP transmission is achieved byconcatenating the multiple pieces of CSI in a bit domain.

According to one aspect of the embodiments of the present invention,there is provided a method for feeding back channel state information,applicable to a CoMP transmission system, the method including:

feeding back channel state information to a network side by way ofconcatenating more than one pieces of channel state information in a bitdomain.

According to another aspect of the embodiments of the present invention,there is provided a method for feeding back channel state information,applicable to a CoMP transmission system, the method including:

selecting one piece of channel state information from a channel stateinformation set indicating feedback; and

transmitting the selected channel state information and signalingindicating the selected channel state information to a network side.

According to still another aspect of the embodiments of the presentinvention, there is provided UE, including:

a feedback unit configured to feed back channel state information to anetwork side by way of concatenating more than one pieces of channelstate information in a bit domain.

According to still another aspect of the embodiments of the presentinvention, there is provided UE, including:

a selecting unit configured to select one piece of channel stateinformation from a channel state information set indicating feedback;and

a transmitting unit configured to transmit the selected channel stateinformation and signaling indicating the selected channel stateinformation to a network side.

According to still another aspect of the embodiments of the presentinvention, there is provided a network system, including a macro basestation, one or more pico base stations and UE; wherein the UE is the UEas described above.

According to still another aspect of the embodiments of the presentinvention, there is provided a computer-readable program, wherein whenthe program is executed in UE, the program enables a computer to carryout the method for feeding back channel state information as describedabove in the UE.

According to still another aspect of the embodiments of the presentinvention, there is provided a storage medium in which acomputer-readable program is stored, wherein the computer-readableprogram enables a computer to carry out the method for feeding backchannel state information as described above in UE.

An advantage of the embodiments of the present invention resides in thata method for feeding back multiple pieces of CSI in a CoMP transmissionmay be provided. Furthermore, RI information and CQI information in theCSI may be respectively encoded and mapped, so as to ensure reliabletransmission of them. In addition, taking working amount ofsimplification of standardization into account, a manner of feeding backRI information and CQI/PMI information in an existing LTE system isreused.

With reference to the following description and drawings, the particularembodiments of the present invention are disclosed in detail, and theprinciple of the present invention and the manners of use are indicated.It should be understood that the scope of the embodiments of the presentinvention is not limited thereto. The embodiments of the presentinvention contain many alternations, modifications and equivalentswithin the spirits and scope of the terms of the appended claims.

Features that are described and/or illustrated with respect to oneembodiment may be used in the same way or in a similar way in one ormore other embodiments and/or in combination with or instead of thefeatures of the other embodiments.

It should be emphasized that the term “includes/including” when used inthis specification is taken to specify the presence of stated features,integers, steps or components but does not preclude the presence oraddition of one or more other features, integers, steps, components orgroups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the embodimentsof the invention will be or become apparent upon examination of thefollowing drawings and detailed description. In the drawings:

FIG. 1 is a flowchart of a method for feeding back channel stateinformation of Embodiment 1 of the present invention;

FIG. 2 is a flowchart of a method for feeding back channel stateinformation of Embodiment 2 of the present invention;

FIG. 3A is a schematic diagram of resource mapping relationship;

FIG. 3B is schematic diagram of resource mapping relationship;

FIG. 4 is a flowchart of a method for feeding back channel stateinformation of Embodiment 3 of the present invention;

FIG. 5 is a flowchart of a method for feeding back channel stateinformation of Embodiment 4 of the present invention;

FIG. 6 is a flowchart of a method for feeding back channel stateinformation of Embodiment 5 of the present invention;

FIG. 7 is a schematic diagram of the structure of UE of Embodiment 6 ofthe present invention;

FIG. 8 is a schematic diagram of the structure of a feedback unit inFIG. 7;

FIG. 9 is a schematic diagram of the structure of the feedback unit inFIG. 7;

FIG. 10 is a schematic diagram of the structure of UE of Embodiment 7 ofthe present invention;

FIGS. 11A is a schematic diagram of the structure of the feedback unitin Embodiment 7;

FIGS. 11B is a schematic diagram of the structure of the feedback unitin Embodiment 7; and

FIG. 12 is a schematic diagram of the structure of UE of Embodiment 8 ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention are described as followswith reference to the drawings. These embodiments are illustrative only,and are not intended to limit the present invention. For the principleand modes of implementation of the present invention to be easilyunderstood by those skilled in the art, the modes of implementation ofthe present invention shall be described taking determination of amethod for feeding back channel state information in a CoMP transmissionsystem as an example. However, it should be understood that the presentinvention is not limited to the above system, and is applicable to othersystems related to feeding back channel state information.

Currently, in LTE Rel. 10, periodic and aperiodic feedback modes areused to provide feedback information of different granularities to UE,so as to improve performance of the system. Wherein, the aperiodicfeedback mode is suitable for a feedback demand of CoMP, as it hasadvantages of a large capacity and small delay. Hence, in thisembodiment, for a CoMP transmission scenario, description is giventaking that CSI in different transmission points and differentinterference assumptions is fed back aperiodically as an example.

In this embodiment, a base station may trigger aperiodic feedback of CSIvia dynamic control information (DCI). Corresponding to a CoMPtransmission mode, when triggering in a common search space, a 1-bitrequest domain in DCI format 0 or DCI format 4 is used to trigger theaperiodic feedback of the CSI; and when triggering in a UE search space,a 2-bit CSI request domain in DCI format 0 or DCI format 4 is used totrigger the aperiodic feedback of the CSI.

In this embodiment, for the aperiodic feedback in the CoMP transmission,one or more pieces of channel state information may be included;wherein, each piece of channel state information (CSI) includesfollowing information: rank indication (RI) information, precodingmatrix indication (PMI) information, and channel quality indication(CQI) information. Wherein, multiple different combinations of theRI/PMI/CQI may be employed according to different feedback modes. Forexample, when the PMI/CQI are discarded, the UE may use a mode 2-0 tofeed back wideband CQI, UE selection subband CQI information and subbandindication information; and the user uses a mode 3-0 to feed backwideband CQI and subband CQI information configured via a high layer,such configuration being suitable for an aperiodic feedback requirementof CoMP UE in a TDD system. And when the PMI/CQI are not discarded, theUE uses a mode 1-2 to feed back RI information, wideband CQI and subbandPMI information; or uses 2-2 to feed back RI information, wideband CQI,UE selection subband differential CQI information, subband selectionidentification information and wideband precoding information; or uses amode 3-1 to feed back RI information, wideband CQI, subband CQI andwideband PMI information, as shown in Table 1.

TABLE 1 PMI feedback type No PMI Single PMI Multiple PMI PUSCH CQIWideband Mode Feedback (Wideband CQI) 1-2 Type UE selected Mode Mode(subband CQI) 2-0 2-2 Higher Mode Mode Layer-configured 3-0 3-1 (subbandCQI)

A network side, such as a macro base station, configures each piece ofCSI with a CSI-RS resource of non-zero power and an interference partmeasurement resource of non-zero power, and the UE may use theseresources to measure and report the CSI. In the CoMP transmission,multiple pieces of CSI corresponding to multiple transmission points(TPs) and interference assumptions need to be reported. Wherein, themultiple pieces of CSI may be multiplexed in a physical uplink sharedchannel (PUSCH) for transmission.

As UE is limited in an actual processing ability at present, the numberof feedback pieces of CSI is limited. In this embodiment, the CSI is fedback to a network side by concatenating more than one pieces of CSI in abit domain. In this way, the above problem may be solved, and it is notonly applicable to a CoMP scenario, but also applicable to amulticarrier scenario and a scenario where aperiodic report of CSI istriggered in a common space. Wherein, according to an actual situation,a UE feedback receiving point may be a macro base station at the networkside, and may also be all base stations at the network side. Theembodiments of the present invention shall be described below in detailwith reference to the drawings taking aperiodic feedback as an example.

FIG. 1 is a flowchart of a method for feeding back channel stateinformation of Embodiment 1 of the present invention. As shown in FIG.1, the method includes:

step 101: receiving, by UE, indication information for aperiodicallyfeeding back CSI transmitted by a network side;

in this embodiment, the network side may indicate, via DCI, toaperiodically feed back the CSI, the number of pieces of the CSI needingto be fed back is 1 or more than 1;

in this embodiment, the macro base station or all the base stations atthe network side may trigger the aperiodic feedback; and when the numberof pieces of the fed back CSI is 1, a mode in the existing Rel. 8 may beemployed, which shall not be described herein any further. A case wheremore than 1 pieces of CSI are fed back shall be described below;

step 102: feeding back the CSI, by the UE to the network side by way ofconcatenating more than one pieces of CSI in a bit domain;

in this embodiment, if the aperiodic feedback is triggered according toa transmission point or a CSI-RS resource of non-zero power, the UEneeds to report CSI in an aperiodic CSI set corresponding to multipledifferent interference assumptions; and if the aperiodic feedback istriggered according to the CSI, the UE needs to report correspondingCSI. With the above embodiment, a method for feeding back multiplepieces of CSI in a CoMP transmission is provided, and multiple pieces ofCSI may be fed back to the network side, without being limited by aprocessing ability of the UE.

In this embodiment, step 102 may be executed in multiple ways, so as toindependently concatenate rank indication (RI) information, precodingmatrix indication (PMI) information and/or channel quality indication(CQI) information in the channel state information in the bit domain,which shall be respectively described below with reference to thedrawings.

FIG. 2 is a flowchart of a method for feeding back CSI of Embodiment 2of the present invention. As shown in FIG. 2, the method includes:

step 200: similar to step 101, which shall not be described herein anyfurther;

step 201: arranging the more than one pieces of CSI in a source bitdomain;

in this embodiment, it can be known that more than one pieces of CSIneed to be fed back according to the indication information of theaperiodic feedback; in this way, the CSI needing to be fed back isarranged in the source bit domain in a certain order;

wherein, the RI information and the PMI/CQI information are respectivelyconcatenated in the bit domain;

step 202: performing corresponding processing to the arranged more thanone pieces of CSI, mapping them to a corresponding resource, andtransmitting them to the network side;

in this embodiment, different encoding and mapping manners are employedfor different CSI, such as RI information and PMI/CQI information; inthis way, performance requirements of the RI information and PMI/CQIinformation may be ensured; and the processes of processing and mappingare similar to those in the prior art, which may simplify a workingamount of standardization. Following description is given by way ofexamples.

For example, for the RI information, when the total number of thearranged bits is less than or equal to 2, the block encoding in Rel. 8may be used; when the number of bits is less than 12 and greater than 2,RM (reed-Muller) encoding of (32, O) is used; and when the number ofbits is greater than 11, dual RM (reed-Muller) encoding of (32, O) isused. A needed number of the bits is obtained from the encodedinformation by using cyclic shift. In mapping, the RI information ismapped into 4 OFDM symbols close to the DM-RS; that is, the mapping isperformed in an order of from the time domain to the frequency domain(an inverse order of the frequency domain) according to the specified 4OFDM symbols(for example, RI information is mapping to (1,4,7,10) innormal CP, and to (0,3,5,8) in expanding CP), as shown in FIG. 3A, withsuch processes of encoding and mapping being similar to those in theprior art, which shall not be described herein any further. In this way,estimated performances of them may be ensured, and reliability oftransmission may be improved.

For example, for the PMI/CQI information, when the number of bits isless than 11, RM (reed-Muller) encoding of (32, O) is used; and when thenumber of bits is greater than 11, tail-biting convolutional encoding isperformed after 8 bits of CRC are added into a source bit. A needednumber of the bits is obtained from the encoded information by usingcyclic shift. In this embodiment, PMI/CQI information and the PUSCHinformation (uplink data) are multiplexed and interleaved, and mappingis performed after the interleaving. Wherein, resources occupied by theRI information and ACK/NACK are punctured in mapping; and in performingmapping from uplink data symbols to physical resources, the PMI/CQIinformation is mapped first, and then the uplink data are mapped in theremaining resources, as shown in FIG. 3A.

In this embodiment, when RI information and PMI/CQI information arecontained in more than one pieces of CSI, the RI information and thePMI/CQI information are respectively concatenated in the bit domain, andprocessing and mapping are performed independently.

It can be seen from the above embodiment that a method for feeding backmultiple pieces of CSI in a CoMP transmission is provided. In the CoMPtransmission mode, the multiple pieces of CSI are ordered in the sourcebit domain first, then corresponding encoding is performed according tothe number of the ordered bits and mapped into corresponding resources,thereby feeding back the multiple pieces of CSI.

FIG. 4 is a flowchart of a method for feeding back CSI of Embodiment 3of the present invention. As shown in FIG. 4, the method includes:

step 400: similar to step 101, which shall not be described herein anyfurther;

step 401: encoding more than one pieces of CSI respectively;

in this embodiment, each piece of CSI in the more than one pieces of CSIis encoded first, and RI information or PMI/CQI information is encodedrespectively, with a manner of encoding being similar to that inEmbodiment 2, which shall not be described herein any further;

step 402: arranging the encoded more than one pieces of CSI in the bitdomain;

in this embodiment, similar to Embodiment 2, the RI information and thePMI/CQI information are ordered respectively;

step 403: mapping the ordered more than one pieces of CSI to acorresponding resource, and transmitting them to the network side;

in this embodiment, similar to Embodiment 2, the RI information and thePMI/CQI information are mapped respectively, with a process of mappingbeing similar to Embodiment 2, which shall not be described herein anyfurther.

It can be seen from the above embodiment that in the CoMP transmissionmode, each piece of CSI in the multiple pieces of CSI is respectivelyencoded first, ordered in the bit domain, and then mapped to acorresponding resource, thereby feeding back the multiple pieces of CSI.

In the above embodiment, in ordering in steps 201 and 402, ordering maybe performed in any order. Furthermore, ordering may be performed inmanners as follows:

1) if the aperiodic feedback is triggered according to a transmissionpoint or a CSI-RS resource of non-zero power, in feeding back CSI in aCSI set corresponding to multiple interference assumptions, the orderingis performed in a fixed order;

for example, the ordering is performed first in an order of feeding backthe channel state information corresponding to CSI-RS resource ofnon-zero power in the CSI set;

and then corresponding to each CSI-RS resource of non-zero power, theordering is performed in a preconfigured order of interferenceassumptions; that is, the ordering is performed in an order of feedingback the corresponding interference assumptions in the CSI set; takingthree transmission points and two interference sources as an example,the fixed order may be (interference started, interference started),(interference started, interference closed), (interference closed,interference started), (interference closed, interference closed). Ofcourse, this is an embodiment of the present invention only, and it maybe another order;

as another form of implementation, such a preconfigured interferenceorder may be acquired via high-layer configuration; for example, inconfiguring an aperiodic CSI feedback set by the base station, CSI ofdifferent interference assumptions of the same CSI-RS of non-zero powerhas a configuration order, and such a configuration order may be used asan order of concatenating; that is, feedback information correspondingto CSI that is configured earlier is placed in front, and CSI that isconfigured later is placed behind;

2) if the aperiodic feedback is triggered according to the CSI, the UEneeds to report corresponding CSI, and ordering is performed in an orderof the configured CSI.

In this embodiment, when there exist two or more identical pieces ofinformation in the more than one pieces of CSI, one piece of theinformation is reserved, thereby saving resources.

The method describe in the above embodiment may be applicable to ascenario of a single carrier. And for a case where CSI on multiplecarriers is fed back, following method may be employed.

FIG. 5 is a flowchart of a method for feeding back CSI of Embodiment 4of the present invention. As shown in FIG. 5, the method includes:

step 500: receiving, by UE, indication information of aperiodic feedbackCSI transmitted by the network side;

in this embodiment, the network side may indicate the aperiodic feedbackCSI via DCI; and in a scenario of multiple carriers, the CSI needing tobe fed back indicated by the indication information includes: CSIneeding to be fed back on different carriers, and CSI needing to be fedback in different transmission points and interference assumptions onthe same carrier;

step 501: concatenating respectively more than one pieces of CSI neededto be fed back for each cell corresponding transmission points andinterference assumptions;

in this embodiment, in concatenating each cell, the methods described inembodiments 2 and 3 may be used, which shall not be described herein anyfurther;

step 502: concatenating CSI of all cells needing to feed back channelstate information;

in this embodiment, CSI of all the cells is arranged in an ascending ordescending order of the cells ID;

step 503: performing corresponding processing to the concatenated CSI ofall the cells, and mapping them to a corresponding resource fortransmitting them to the network side;

in this embodiment, manners of processing and mapping are similar tothose described in embodiments 2 and 3, which shall not be describedherein any further.

In the above embodiment, possible CSI sets in the CoMP transmission areconcatenated first for each carrier, and then all the carriers areconcatenated.

In another mode of implementation, concatenating is performed in acarrier domain first (bit ordering), and then possible CSI sets in theCoMP transmission are concatenated for each carrier. Following is aparticular process:

concatenating channel state information of all the cells needing to feedback channel state information (CSI of all the cells is arranged in anascending or descending order of the cells ID); concatenatingrespectively more than one pieces of channel state information needed tobe fed back for each cell (the methods in embodiments 2 and 3 may beused); and mapping the concatenated channel state information to acorresponding resource for transmitting to the network side.

FIG. 3B is an example of a CoMP system. Wherein, for a case where CoMPis combined with CA, in comparison with FIG. 3A, concatenating of a stepof carrier domain is added. Wherein, FIG. 3B does not mean thatconcatenating is performed before and after encoding, but means an orderin ordering. Wherein, numbers “11” and “12” are a first piece of CSI anda second piece of CSI on a first carrier, and numbers “21” and “22” area first piece of CSI and a second piece of CSI on a second carrier.

It can be seen from the above embodiment that with the method above, theproblem of feedback of CSI in a case where multiple carriers arecombined with CoMP transmission may be solved, and transmission rate ofthe UE may be improved by the technology in which the CoMP transmissionand carrier aggregation are combined.

When the UE triggers aperiodic report of CSI in a common space, if CSIreport of a single cell is triggered only, the transmission method inRel. 8 may be employed, and the method of this embodiment needs not tobe employed.

In order to further obtain a good compromise between feedback overheadand system performance, the UE may perform down-selection of theaperiodic report of the CSI set configured by the base station.

FIG. 6 is a flowchart of a method for feeding back channel stateinformation of Embodiment 5 of the present invention. As shown in FIG.6, the method includes:

step 600: receiving indication information of aperiodic feedback CSItransmitted by the network side;

step 601: selecting one piece of CSI from a CSI set indicating feedbackin the indication information;

in this embodiment, the UE may select optimal CSI from the CSI setaccording to the indication information; for example, CSI, or the like,transmitting a maximum amount of information, may be selected;

step 602: transmitting the selected one piece of channel stateinformation and signaling indicating the selected channel stateinformation to a network side;

in this embodiment, the signaling indicating the selected channel stateinformation may be placed after precoding matrix indication informationand/or channel quality indication information in the selected channelstate information, and the signaling is bit signaling;

wherein, the number of bits is log₂ ^(N), N being a maximum number ofbits; and a value of N is in consistent with the number of theconfigured CSI-RSs of non-zero power or the pre-configured number ofpieces of the CSI of CSI set capable of performing aperiodic feedback.

Such a feedback manner may be carried out in certain specific aperiodicfeedback modes, such as mode 2-2; however, it is not limited thereto.

In this embodiment, in step 601, in order to support backoff, the UE maynot only feed back one piece of optimally selected CSI, but also feedback CSI of a single cell for backoff. Wherein, the CSI of the singlecell for backoff may be CSI defined by a first CSI-RS of non-zero power,or a first piece of CSI in the CSI set capable of performing aperiodicfeedback configured by the base station for the UE, or the CSI of thesingle cell for backoff is determined by a CSI resource supportingbackoff and configured via a high layer. In a feedback process, a CQIfeedback information part in the CSI preferably selected by the UE andthe CQI feedback information in the CSI for backoff are differentiallyencoded, so as to reduce feedback overhead. And in the feedback CSI, thepiece of CSI preferably selected by the UE is arranged after the CSI ofthe single cell for backoff.

It can be seen from the above embodiment that for aperiodic feedback ofCSI, the CSI may be fed back by concatenating in the bit domain, andtaking joint transmission of CoMP and carriers into account, acorresponding method for feeding back CSI is also provided. For furtherobtaining a compromise between feedback overhead and system performancegain, the UE selects an optimal piece of CSI in a down-selection manner;and for supporting backoff, CSI of a single cell may also be selected.

A person of ordinary skill in the art may understand that all or part ofthe steps in the method carrying out the above embodiment may be carriedout by related hardware instructed by a program. The program may bestored in a computer-readable storage medium. And when being executed,the program may include all or part of the steps in the method in theabove embodiment, and the storage medium may include an ROM, an RAM, afloppy disc, and a compact disc, etc.

An embodiment of the present invention further provides UE feeding backCSI, as described in the embodiment below. As the principle of the UEfor solving problems is similar to that of the above method for feedingback CSI, the implementation of the method may be referred to for theimplementation of the UE, and the repeated parts shall not be describedany further.

FIG. 7 is a schematic diagram of the structure of UE of Embodiment 6 ofthe present invention. As shown in FIG. 7, the UE 700 includes:

a feedback unit 701 configured to feed back CSI to a network side by wayof concatenating more than one pieces of CSI in a bit domain.

In a case of aperiodically feeding back CSI, the UE further includes afirst receiving unit 702 configured to receive indication information ofaperiodic feedback CSI transmitted by the network side; in this way, thefeedback unit 701 is configured to feed back the CSI according to theindication information.

In this embodiment, a working flow of the UE 700 is as described inEmbodiment 1 shown in FIG. 1, which shall not be described herein anyfurther.

In this embodiment, the feedback unit 701 independently concatenatesrank indication information and precoding matrix indication informationand/or channel quality indication information in the channel stateinformation in the bit domain. Details are as described aboveEmbodiments, which shall not be described herein any further.

FIG. 8 is a schematic diagram of the structure of the feedback unit inFIG. 7. As shown in FIG. 8, the feedback unit 701 includes: a firstordering unit 801 and a first processing unit 802; wherein,

the first ordering unit 801 is configured to arrange the more than onepieces of CSI in a source bit domain; wherein, a manner of ordering issimilar to step 201 of Embodiment 2, which shall not be described hereinany further;

and the first processing unit 802 is configured to perform correspondingprocessing to the arranged more than one pieces of CSI and map them to acorresponding resource for transmitting to the network side. Wherein,the processes of processing and mapping are similar to step 202 ofEmbodiment 2, which shall not be described herein any further.

It can be seen from the above embodiment that in concatenating more thanone pieces of CSI in the bit domain, ordering may be performed first,and then mapping to a corresponding resource is performed fortransmitting after corresponding processing is performed.

FIG. 9 is a schematic diagram of the structure of the feedback unit inFIG. 7. As shown in FIG. 9, the feedback unit 701 includes: a secondprocessing unit 901, a second ordering unit 902 and a third processingunit 903; wherein,

the second processing unit 901 is configured to encode respectively themore than one pieces of CSI; wherein a method of encoding by the secondprocessing unit 901 is as described in Embodiment 2, which shall not bedescribed herein any further;

the second ordering unit 902 is configured to arrange the encoded morethan one pieces of CSI in the bit domain; wherein a method of orderingby the second ordering unit 902 is similar to those described inembodiments 2 and 3, which shall not be described herein any further;

and the third processing unit 903 is configured to map the arranged morethan one pieces of CSI to a corresponding resource, and transmit them tothe network side; wherein a manner of mapping by the third processingunit 903 is as described in Embodiment 3, which shall not be describedherein any further.

It can be seen from the above embodiment that in concatenating more thanone pieces of CSI in the bit domain, they may be respectively encodedfirst, then ordered, and mapped to a corresponding resource fortransmission.

In the above embodiment, when the CSI contains RI information andPMI/CQI information, the first processing unit 802 or the secondprocessing unit 901 and the third processing unit 903 may independentlyprocess and map the RI information and PMI/CQI information, and orderthem in the bit domain respectively.

In the above embodiment, the first ordering unit 801 or the secondordering unit 902 is further configured to arrange the more than onepieces of channel state information in the source bit domain or arrangethe encoded more than one pieces of channel state information in the bitdomain in a fixed order or in a configured order of the channel stateinformation. Details are as described in Embodiment 3, which shall notbe described herein any further.

In this embodiment, the first ordering unit 801 or the second orderingunit 902 reserves one piece of the information when there existsidentical two or more pieces of information restricted by an assumptionin the more than one pieces of channel state information, so as tosimplify a procedure of processing.

The UE feeding back CSI in a scenario where multiple carriers and theCoMP transmission are combined shall be described below.

FIG. 10 is a schematic diagram of the structure of UE of Embodiment 7 ofthe present invention. As shown in FIG. 10, the UE 1000 includes areceiving unit 1001 and a feedback unit 1002; wherein the functions ofthe receiving unit 1001 and the feedback unit 1002 are similar to thosedescribed in Embodiment 6, with an exception that the CSI needing to befed back indicated by the indication information received by thereceiving unit 1001 includes: CSI needing to be fed back on differentcarriers, and CSI needing to be fed back in different transmissionpoints and interference assumptions on the same carrier.

As shown in FIG. 11A, the feedback unit 1002 includes:

a fourth processing unit 1101 configured to concatenate respectivelymore than one pieces of channel state information in a correspondingtransmission point of each cell; a third ordering unit 1102 configuredto concatenate channel state information of all cells; and a fifthprocessing unit 1103 configured to encode the new concatenated stateindication information of all the cells, and map it to correspondingresources to feed back to the network side.

The fourth processing unit 1101, the third ordering unit 1102 and thefifth processing unit 1103 in the above embodiment are similar to steps501-503 in Embodiment 4, which shall not be described herein anyfurther.

As shown in FIG. 11B, the feedback unit 1002 includes:

a fourth ordering unit 1101′ configured to concatenate channel stateinformation of all cells needing to feed back channel state information;a sixth processing unit 1102′ configured to concatenate respectivelymore than one pieces of channel state information needed to be fed backfor each cell; and a seventh processing unit 1103′ configured to map theconcatenated channel state information to corresponding resources tofeed back to the network side. In this embodiment, the third orderingunit 1102 and the fourth ordering unit 1101′ is further configured toarrange channel state information of all the cells in an ascending ordescending order of the cells ID.

In order to further obtain a good compromise between feedback overheadand system performance, the UE may perform down-selection of theaperiodic report of the CSI set configured by the base station.

FIG. 12 is a schematic diagram of the structure of UE of Embodiment 8 ofthe present invention. As shown in FIG. 12, the UE 1200 includes: aselecting unit 1201 and a transmitting unit 1202; wherein,

the selecting unit 1201 is configured to select one piece of channelstate information from a preconfigured channel state information set forfeeding back to a network side; and the transmitting unit 1202 isconfigured to transmit the selected channel state information to thenetwork side.

In this embodiment, the transmitting unit 1202 is configured to transmitthe selected channel state information and signaling indicating theselected channel state information to the network side.

Wherein, the bit signaling indicating the selected channel stateinformation is placed after precoding matrix indication informationand/or channel quality indication information in the selected channelstate information.

In order to support backoff, the selecting unit 1201 of the UE 1200 mayfurther select CSI of a single cell; wherein the channel stateinformation of the single cell for backoff is channel state informationto which a first channel state indication reference signal resource ofnon-zero power corresponds or a first piece of channel state informationin the channel state information set, or the channel state informationof the single cell for backoff is determined by a anchor channel stateinformation resource supporting backoff configured via a high layer.

For aperiodic feedback, the UE 1200 may further include a secondreceiving unit (not shown) configured to receive indication informationfor aperiodically feeding back channel state information transmitted bythe network side, and the selecting unit 1201 is further configured toselect channel state information to be fed back to the network sideaccording to the indication information.

In this embodiment, working processes of the selecting unit 1201 and thetransmitting unit 1202 are similar to those in Embodiment 5, which shallnot be described herein any further.

It can be seen from the above embodiment that for aperiodic feedback ofCSI, the CSI may be fed back by concatenating in the bit domain, andtaking joint transmission of CoMP and carriers into account, acorresponding method for feeding back CSI is also provided. For furtherobtaining a compromise between feedback overhead and system performancegain, the UE selects an optimal piece of CSI in a down-selection manner;and for supporting backoff, CSI of a single cell may also be selected.

Embodiment 9 of the present invention further provides a network system,including a macro base station, one or more pico base stations and UE;wherein the UE is the UE as described in the above embodiment, whichshall not be described herein any further. And the macro base stationand the pico base station(s) at the network side are configured totransmit to the UE indication information triggering aperiodic feedback.

An embodiment of the present invention further provides acomputer-readable program, wherein when the program is executed in UE,the program enables a computer to carry out the method for feeding backchannel state information as described in the above embodiments in theUE.

An embodiment of the present invention further provides a storage mediumin which a computer-readable program is stored, wherein thecomputer-readable program enables a computer to carry out the method forfeeding back channel state information as described in the aboveembodiments in UE.

In the above embodiment, the UE may any terminal equipment, such as amobile phone, a PDA, and a computer, etc.

The above apparatuses and methods of the present invention may beimplemented by hardware, or by hardware in combination with software.The present invention relates to such a computer-readable program thatwhen the program is executed by a logic device, the logic device isenabled to carry out the apparatus or components as described above, orto carry out the methods or steps as described above. The presentinvention also relates to a storage medium for storing the aboveprogram, such as a hard disk, a floppy disk, a CD, a DVD, and a flashmemory, etc.

The present invention is described above with reference to particularembodiments. However, it should be understood by those skilled in theart that such a description is illustrative only, and not intended tolimit the protection scope of the present invention. Various variantsand modifications may be made by those skilled in the art according tothe spirits and principle of the present invention, and such variantsand modifications fall within the scope of the present invention.

What is claimed is:
 1. A method for feeding back channel stateinformation, applicable to a CoMP transmission system, the methodcomprising: feeding back channel state information to a network side byway of concatenating more than one pieces of channel state informationin a bit domain.
 2. The method according claim 1, wherein rankindication information and precoding matrix indication informationand/or channel quality indication information in the channel stateinformation are independently concatenated in the bit domain.
 3. Themethod according to claim 1, wherein the method further comprises:receiving indication information of aperiodic feedback channel stateinformation transmitted by the network side; and the feeding back thechannel state information comprises: feeding back the channel stateinformation according to the indication information; wherein rankindication information and precoding matrix indication informationand/or channel quality indication information in the channel stateinformation are independently concatenated in the bit domain.
 4. Themethod according to claim 1, wherein the method comprises: arranging themore than one pieces of channel state information in a source bitdomain; and performing corresponding processing to the arranged morethan one pieces of channel state information, mapping them to acorresponding resource, and transmitting them to the network side;wherein rank indication information and precoding matrix indicationinformation and/or channel quality indication information in the channelstate information are independently concatenated in the bit domain. 5.The method according to claim 1, wherein the method comprises: arrangingthe more than one pieces of channel state information in a source bitdomain; and performing corresponding processing to the arranged morethan one pieces of channel state information, then mapping them to acorresponding resource, and transmitting them to the network side;wherein when feeding back channel state information in a feedbackchannel state information set corresponding to multiple interferenceassumptions, the more than one pieces of channel state information arearranged in the source bit domain in a fixed order; and in feeding backthe channel state information, the more than one pieces of channel stateinformation are arranged in the source bit domain in an order of theconfigured channel state information.
 6. The method according to claim1, wherein in feeding back channel state information on more than onecarriers, the method comprises: concatenating respectively more than onepieces of channel state information needed to be fed back for each cell;concatenating channel state information of all cells needing to feedback channel state information; and mapping the concatenated channelstate information of all the cells to corresponding resources andfeeding back to the network side.
 7. The method according to claim 6,wherein the concatenating channel state information of all cells needingto feed back channel state information comprises: arranging channelstate information of all the cells in an ascending or descending orderof the cells ID.
 8. UE, comprising: a feedback unit configured to feedback channel state information to a network side by way of concatenatingmore than one pieces of channel state information in a bit domain. 9.The UE according to claim 8, wherein the feedback unit independentlyconcatenates rank indication information and precoding matrix indicationinformation and/or channel quality indication information in the channelstate information in the bit domain.
 10. The UE according to claim 8,wherein the UE further comprises: a first receiving unit configured toreceive indication information of aperiodic feedback channel stateinformation transmitted by the network side; and the feedback unit isfurther configured to feed back the channel state information accordingto the indication information; wherein the feedback unit independentlyconcatenates rank indication information and precoding matrix indicationinformation and/or channel quality indication information in the channelstate information in the bit domain.
 11. The UE according to claim 8,wherein the feedback unit comprises: a first ordering unit configured toarrange the more than one pieces of channel state information in asource bit domain; and a first processing unit configured to performcorresponding processing to the arranged more than one pieces of channelstate information and map them to a corresponding resource fortransmitting to the network side; wherein the feedback unitindependently concatenates rank indication information and precodingmatrix indication information and/or channel quality indicationinformation in the channel state information in the bit domain.
 12. TheUE according to claim 8, wherein the feedback unit comprises: a firstordering unit configured to arrange the more than one pieces of channelstate information in a source bit domain; and a first processing unitconfigured to perform corresponding processing to the arranged more thanone pieces of channel state information and map them to a correspondingresource for transmitting to the network side; wherein the firstordering unit or the second ordering unit is further configured toarrange the more than one pieces of channel state information in thesource bit domain or arrange the encoded more than one pieces of channelstate information in the bit domain in a fixed order or in an order ofthe configured channel state information.
 13. The UE according to claim8, wherein the feedback unit comprises: a first ordering unit configuredto arrange the more than one pieces of channel state information in asource bit domain; and a first processing unit configured to performcorresponding processing to the arranged more than one pieces of channelstate information and map them to a corresponding resource fortransmitting to the network side; wherein the first ordering unit or thesecond ordering unit is further configured to arrange the more than onepieces of channel state information in the source bit domain or arrangethe encoded more than one pieces of channel state information in the bitdomain in a fixed order or in an order of the configured channel stateinformation; wherein when feeding back channel state information in afeedback channel state information set corresponding to multipleinterference assumptions, the arranging in a fixed order refers to:arranging in the order of the channel state information in the feedbackchannel state information set corresponding to channel state indicationreference signal resources of non-zero power, and corresponding to eachof the channel state indication reference signal resources of non-zeropower, arranging in a fixed or high-layer configured order ofinterference assumptions; wherein in feeding back channel stateinformation on more than one carriers, the feedback unit comprises: afourth ordering unit configured to concatenate channel state informationof all cells needing to feed back channel state information; a sixthprocessing unit configured to concatenate respectively more than onepieces of channel state information needed to be fed back for each cell;and a seventh processing unit configured to map the concatenated channelstate information to corresponding resources and feed back to thenetwork side.
 14. The UE according to claim 13, wherein the thirdordering unit or the fourth ordering unit is further configured toarrange channel state information of all the cells in an ascending ordescending order of the cells ID.
 15. A network system, comprising amacro base station, one or more pico base stations and UE; wherein theUE is the UE as claimed in claim 8.